Submitted December 17, 2003
Returned for revision January 12, 2004
Accepted February 2, 2004
Testis
Testicular Activity of Mos in the Frog, Rana
esculenta: A New Role in Spermatogonial Proliferation
Diana Ferrara ,
Carmela Palmiero ,
Margherita Branno ,
Riccardo Pierantoni *,
and
Sergio Minucci
* To whom correspondence should be addressed. E-mail: riccardo.pierantoni{at}unina2.it.
Abstract
Mos is a MAPK kinase kinase whose expression is highly
restricted to the gonads. Its function is mainly
associated to the meiotic metaphase II arrest occurring
during female gametogenesis, while its role during
spermatogenesis has not yet clarified.
In this paper we report the isolation of c-mos cDNA and
the identification of a 60 kDa Mos protein from the testis
of the anuran amphibian, Rana esculenta. Both the
transcript and the protein are always present at low
levels in the testis during the frog annual sexual cycle,
with single significant peaks of expression in March and
May, respectively. Mos is mainly localized in the
cytoplasm of primary and secondary spermatogonia (I and II
SPG). Therefore, we have used treatments with
ethane-dimethane sulphonate (EDS) which is proved to block
spermatogonial mitosis in frogs. Four days after a single
EDS injection, Mos expression in SPG highly increases
concomitantly to the temporary arrest of mitosis; from 8
to 28 days after the injection, the normal proliferative
activity of SPG is restored and Mos expression
gradually decreases to control levels. These results
strongly indicate that c-mos proto-oncogene
exerts a new role associated to the regulation of
spermatogonial proliferation.
Key words:
Testis •
Spermatogenesis
